836. Rectangle Overlap

class Solution 
{
public:
    bool isRectangleOverlap(vector<int>& rec1, vector<int>& rec2) 
    {
        return rec1[0]<rec2[2]&&rec2[0]<rec1[2]&&rec1[1]<rec2[3]&&rec2[1]<rec1[3];
    }
};

r1left      r2left     r1right      r2right

一个方向上的判定条件：left1<right2&&left2<right1

用两个方向上的判定即可